XAGE-1 Background Information XAGE-1 is a cancer testis antigen with an expression pattern that is limited to germ cells of the testis and a variety of neoplastic tissues, but is abundantly expressed in breast, prostate and lung cancer, as well as in Ewing’s sarcomas and rhabdomyosarcomas. The XAGE-1 gene lies on the X chromosome and encodes for a 146 amino acid protein. XAGE-1 expression in normal and cancerous tissues is regulated by methylation of the CpG island in the gene promoter. Four transcript variants of XAGE-1 (XAGE-1a-d) exist, and XAGE-1b and XAGE-1d are specifically overexpressed in lung cancer. Because XAGE-1 is present in such a diverse range of cancers, it may be useful as a target for many cancer immunotherapies.
